The maximal angle condition on finite elements: useful or not?

On the Displacement-Stress Continuous Finite Elements

For the analysis of composite media, three different compatible and mixed finite element formulations are presented which apriori enforce the continuity of stresses as well as displacements at the element interfaces. The formulations are applied for the analysis of hi-material interfaces in two problems often encountered in the field of orthopaedic biomechanics, that is the fixation analysis in...

On the maximal angle between copositive matrices

Hiriart-Urruty and Seeger have posed the problem of finding the maximal possible angle θmax(Cn) between two copositive matrices of order n [J.-B. Hiriart-Urruty and A. Seeger. A variational approach to copositive matrices. SIAM Rev., 52:593–629, 2010.]. They have proved that θmax(C2) = 3 4 π and conjectured that θmax(Cn) is equal to 3 4 π for all n ≥ 2. In this note, their conjecture is disprov...

Maximal subsets of pairwise non-commuting elements of some finite p-groups

Let G be a group. A subset X of G is a set of pairwise noncommuting elements if xy ̸= yx for any two distinct elements x and y in X. If |X| ≥ |Y | for any other set of pairwise non-commuting elements Y in G, then X is said to be a maximal subset of pairwise non-commuting elements. In this paper we determine the cardinality of a maximal subset of pairwise non-commuting elements in any non-abelian...

Some Results on Maximal Elements

We prove some results on maximal elements using the KKM-map principle.

Maximal Length Elements of Excess Zero in Finite Coxeter Groups